Cheers. That (the JM soundalikee thing) was the lazy criticism that people used. Rather like dismissing the Bell Hollow singer as a Morrisy soundalikee (look 'em up - smashing band).
Also at the time (1979), gloom and doom and darker sounding stuff was not fashionable. Take a look at 1979's...
Story has it he was having fits on stage but I never blieved it.
I found and downloaded the entire album by Warsaw recently. Quite punky, some protoversions of JD songs, and IC singing in a higher register. Indeed, a five second search and here you go...
https://www.youtube.com/watch?v=6Te60uSCSQA